Role of Schmallenberg virus infection in congenital malformations in ruminants in Scotland in 2017.

Scotland's Rural College (SRUC), together with the Moredun Research Institute, carries out surveillance for Schmallenberg virus (SBV) infection in cattle and sheep. This article reports findings relating to diagnoses of fetopathy associated with SBV infection and other congenital malformations in these species made between January 1 and May 5, 2017.

Analysis of bovine viral diarrhoea virus: Biobank and sequence database to support eradication in Scotland.

Samples from bovine viral diarrhoea virus (BVDV)-positive cattle were gathered by Scottish diagnostic laboratories and used to produce a Biobank of samples with associated location and identification data in support of the Scottish BVDV eradication scheme. The samples were subject to direct amplification and sequencing of the 5'-untranslated region (5'-UTR) to define the viral types and subtypes present. From 2693 samples collected prior to 2016, approximately 2300 sequences were obtained, representing 8 BVDV type 1 subtypes. No BVDV type 2 samples were detected. The samples came from all regions of the UK but 66 per cent were from Scotland. Analysis of the sequences showed great diversity in the 5'-UTR, with 1206 different sequences. Many samples carried virus with identical 5'-UTR sequences; often from single locations, but there were also examples of the same sequence being obtained from samples at several different locations. This work provides a resource that can be used to analyse the movement of BVDV strains both within Scotland and between Scotland and other nations, particularly in the latter stages of the Scottish eradication programme, and so inform the advice available to both livestock keepers and policymakers.

Clostridium perfringens type-D enterotoxaemia in cattle: the diagnostic significance of intestinal epsilon toxin.

The aims of this study were to describe 42 cases of Clostridium perfringens type-D enterotoxaemia in cattle seen between 2003 and 2014 and to determine the diagnostic value of detecting epsilon toxin in bovine intestinal content. All cases in the series had histological brain changes considered pathognomonic for C. perfringens type-D enterotoxaemia in sheep and goats and the epsilon toxin of C. perfringens was concurrently detected in the intestinal contents of 15 (36 per cent) cases. The data from the case series indicate that intestinal epsilon toxin has a sensitivity of 56 per cent compared with histology of the brain for diagnosis of bovine C. perfringens type-D enterotoxaemia. The diagnostic specificity of detecting epsilon toxin in bovine intestinal content was investigated by screening intestinal contents of 60 bovine carcases submitted for postmortem examination. Epsilon toxin was detected in 11 (18 per cent) carcases but no pathognomonic histological brain change was found in any. The specificity of intestinal epsilon toxin was estimated to be 80.4 per cent. These studies demonstrate that for a definitive diagnosis of C. perfringens type-D enterotoxaemia in cattle histological examination of the brain is essential as the presence of epsilon toxin in the intestinal contents alone is neither sensitive nor specific enough.

Field study of pneumonia in vaccinated cattle associated with incorrect vaccination and Pasteurella multocida infection.

This field study used data on the vaccine courses against bovine respiratory disease sold by one pharmaceutical company in conjunction with pharmacovigilance data to explore reported suspected lack of expected efficacy and the reasons for this. The study ran from May 1, 2007, to April 30, 2010, and covered vaccines sold in Scotland and part of Northumberland. In total, 83 groups of cattle reported suspected lack of expected efficacy, representing 1.6 per cent of the 804,618 vaccine courses sold. It was possible to investigate 45 of these outbreaks in depth using a standard questionnaire and diagnostic protocol. Vaccine usage outwith the specific product characteristics (SPC) occurred in 47 per cent of cases (21/45). The proportion of vaccination courses used where a pathogen contained in the vaccine was detected in the diseased cattle and vaccine use was consistent with the SPC was estimated at 0.12 per cent of the courses sold. Pasteurella multocida was the most common pathogen detected and was found in 21 of the outbreaks. For outbreaks where a pathogen contained in the vaccine was detected, P. multocida was found at a significantly greater frequency (P=0.03) where vaccine use was compliant with the SPC (five of six outbreaks) compared with outbreaks where vaccine use had not been compliant with the SPC (one of seven outbreaks). The limitations of the study, including the diagnostic tests employed and definition of vaccination outwith the SPC, are discussed.

A field comparison of the efficacy and tolerance of marbofloxacin in the treatment of bovine respiratory disease.

A multicentre, controlled, randomized and blinded trial was carried out in 180 ruminating calves with pyrexia and respiratory sign(s) on nine Belgian, British and French farms. All animals were sampled for pathogenic bacteria before treatment and at failure/relapse. Calves were injected with either marbofloxacin (M) solution [Marbocyl (Laboratoire Vétoquinol, Lure, France) 10%] at 2 mg/kg/24 h for 4 days intravenously on the first day then subcutaneously, or tilmicosin (T) solution (Micotil, Elanco Products Ltd, Basingstoke, Hants, UK) at 10 mg/kg as a single subcutaneous (s.c.) injection. The animals were examined clinically eight times up to day 28. The bacterial pathogens were found to be sensitive to marbofloxacin: for Pasteurella haemolytica the minimum inhibitory concentration (MIC)90 was 0.08 microg/mL and for P. multocida the MIC90 was 0.04 microg/mL. Cure rates at day 4 for group M and group T were 84 vs. 82%, respectively (P > or = 0.05). However, overall clinical score was significantly lower after 1 day in group M (P < 0.05). There was no difference in either relapse rate or average daily weight gain between groups. Marbofloxacin was found to be better tolerated than tilmicosin at the s.c. injection site (77.5 vs. 42.2% calves without local swelling, P=0.001) and was well tolerated when injected intravenously. Marbofloxacin was shown to have comparable but faster efficacy and better local tolerance than tilmicosin in the treatment of bovine respiratory disease (BRD).

Clinical, pathological and epidemiological findings in three outbreaks of ovine protozoan myeloencephalitis.

Ovine protozoan myeloencephalitis is a disease of sheep associated with the apicomplexan protozoan Sarcocystis tenella. This paper describes the clinical, pathological and epidemiological findings in three affected flocks from a well-defined geographical area. Clinical signs were restricted to sheep under one year old in their first winter and were first observed at least 42 days after they had been moved off the hill grazing areas to low ground pasture, or after they were given conserved forage. The findings are discussed in relation to the timescale of the life cycle of S. tenella and it is suggested that clinical disease was precipitated by the change from a low level of exposure to infection on the hill to a high level of exposure through contaminated pasture or forage. Possible preventive strategies are discussed.

Abortion in foxhounds and a ewe flock associated with Salmonella montevideo infection.

Salmonella montevideo is a recognised cause of ovine abortion and can cause disease in other domestic animals and humans. The organism was isolated from the aborted fetuses of a bitch from a pack of foxhounds. The subsequent collection of rectal swabs from the foxhounds at approximately two week intervals over a 48-day period resulted in the isolation of S montevideo from 50 of the 61 hounds in the pack on one or more occasions. Some of the hounds had gained access to an open pit containing dead ewes and aborted fetuses on a farm where the housed ewe flock was experiencing S montevideo infection. The S montevideo isolates from both the ovine and canine samples had a plasmid of 120 kilobases with an identical restriction endonuclease fragmentation pattern. The only other isolate from a contemporary outbreak lacked this plasmid. It was concluded that this case offered further evidence of the potential for salmonella infection to be spread by the scavenging of carcasses.

Monensin toxicity in a flock of ostriches.

A total of 42 birds from a flock of 104 farmed ostriches showed signs of toxicity after the accidental inclusion of monensin in their concentrate ration. The initial clinical signs were muscle weakness and ataxia which progressed to recumbency, dyspnoea and death, despite intensive supportive therapy. The serum activity of the enzymes creatine kinase, aspartate aminotransferase and lactate dehydrogenase was high in the affected birds, indicating significant muscle pathology. Few gross lesions were identifiable postmortem, but widespread lesions of degenerative myopathy were present at the histopathological level. However, these degenerative changes were restricted to the skeletal muscle and there was no evidence of cardiomyopathy in any of the birds examined. The birds were fed a ration which contained 215 to 224 ppm monensin for 13 days. New clinical cases ceased to occur shortly after the withdrawal of the source of monensin, but all the individuals which showed clinical signs of toxicity died or were euthanased on humane grounds.

Neosporosis and bovine abortion in Scotland.

Serum samples were collected over a two-year period from aborting cows and their fetuses from throughout Scotland; 465 maternal sera were examined using an immunofluorescent antibody test for IgG antibody to Neospora caninum and 547 fetal sera were examined for IgM and IgG antibody to the parasite; 355 of the maternal sera were paired with their respective fetal samples. The maternal titres ranged from 1/8 to 1/16,384, with 59 per cent (275) having titres of 1/128 or 1/256. Of the 547 fetal sera, 9.9 per cent had IgM titres equal to or greater than 1/64, 11.2 per cent had IgG titres equal to or greater than 1/64 and 15.9 per cent had IgM and/or IgG titres equal to or greater than 1/64. It is concluded that a fetal IgM or IgG titre of 1/64 or more is evidence of fetal exposure to N caninum but that the examination of maternal sera is less reliable on an individual basis, although valuable for indicating the degree of infection in a herd. Although fetal seropositivity does not necessarily provide proof that N caninum was the cause of death in a given case, the observation that 15.9 per cent of aborted fetuses had antibody to the parasite shows that vertical transmission from dam to fetus is relatively common and may be an important cause of fetal loss in cattle in Scotland.

Necrotising enteritis in suckled calves.

Necrotising enteritis is a newly recognised disease affecting two to three-month-old suckled calves in Scotland. A cohort of 10 calves from an affected herd was closely monitored from birth until the risk period was over, and one case occurred. In addition, all the cases of dysentery in suckled calves reported to SAV Veterinary Services, St Boswells, from April to August of 1992 were investigated and a further five outbreaks of necrotising enteritis were identified. The clinical pathology, gross and histological findings and results of microbiological investigations are described. No aetiological agent was identified and although the condition bore a superficial resemblance to mucosal disease the histological changes were distinct from those of mucosal disease and no bovine viral diarrhoea virus antigen was detected.

An estimate of the prevalence of enzootic abortion of ewes in Scotland.

The prevalence of enzootic abortion of ewes in Scotland was estimated over a period of five years. Between 1987 and 1991, 30.7 per cent of all flocks with breeding ewes in Scotland submitted ovine abortion material, and of these flocks 28 per cent showed evidence of the infection, giving a prevalence of 8.6 per cent. Regional differences were observed in both the submission rate and the prevalence.

Associations between viral infections and respiratory disease in artificially reared calves.

Market-purchased, week-old, dairy bred calves entering a commercial calf-rearing unit were blood sampled at six-week intervals until three months old. Viral infections were monitored by ELISA for antibodies to bovine herpesvirus 1, bovine respiratory syncytial virus, parainfluenzavirus-3, bovine adenovirus subgroup 1 and bovine viral diarrhoea virus (BVDV). The immunoperoxidase test was used to detect BVDV in serum. The total immunoglobulin concentration in the initial blood sample was measured by the zinc sulphate turbidity test. The relationship between clinical respiratory disease, viral seroconversion and the initial concentration of serum immunoglobulin was investigated by the use of the relative risk statistic, Fisher's exact test, chi 2 techniques and the correlation coefficient. Treatment rates for respiratory disease of 45 per cent were observed during the first period of the study and 19 per cent during the second period. During the first period there was a significant positive association between clinical respiratory disease and seroconversion for all the viruses except parainfluenzavirus-3 and BVDV but in the second period there was no such relationship. Similarly, in the first period, but not in the second, there was a significant negative association between clinical respiratory disease and both antiviral immunoglobulin as measured by ELISA and total immunoglobulin as measured by the zinc sulphate turbidity test. Two of the 536 calves that survived to three months of age were found to be persistently infected with BVDV.

Urea poisoning in suckler cows.

Accidental urea intoxication resulted in the death of 17 of 29 suckler cows within six hours after the contamination of their drinking water with urea fertiliser. The other cows showed no lasting ill effects and neither their three-month-old calves nor the stock bull were affected. The urea concentration in the water was 86 mmol/litre, and the concentrations of ammonia nitrogen in the rumen fluid of two of the cows which were examined after death were 1825 and 957 mg/litre. The clinical signs and post mortem findings are described.

Comparison of two early season anthelmintic programmes on a commercial beef farm.

Two early season suppressive anthelmintic programmes, ivermectin given three, eight and 13 weeks after turn out and a morantel sustained release bolus administered at turn out, were compared on a commercial farm. The morantel treated cattle grew significantly faster than the ivermectin treated group during the period of treatment, on average at 0.80 kg/day compared with 0.71 kg/day (P less than 0.01). In the second half of the grazing season (13 to 25 weeks after turn out) the ivermectin treated group grew faster than the morantel treated group although the difference was not statistically significant. Over the entire grazing season there was no significant difference in average growth rate between the morantel treated group which grew at 0.80 kg/day and the ivermectin treated group which grew at 0.77 kg/day. These results were related to pasture larval counts, faecal egg counts and plasma pepsinogen levels throughout the grazing period. It was concluded that the morantel sustained release bolus allowed growing cattle to reach their production potential during the period of treatment. However, its efficacy in maintaining production throughout the grazing season was reduced by the 90 day treatment period which failed to give the level of control of gastrointestinal nematode parasites achieved by the 105 day period of treatment in the ivermectin programme.

Associations between viral infection and respiratory disease in young beef bulls.

Blood samples were taken from bull calves at two Meat and Livestock Commission performance testing centres, just after weaning at six months of age and at six weekly intervals until the end of the performance test seven months later. Sera were assayed by specific ELISAS for antibodies to bovine herpes virus 1 (BHV1), respiratory syncytial virus, parainfluenza 3 (Pi3) and adenoviruses A and B. Seroconversions between each sampling were related to the occurrence of clinical respiratory disease using chi-squared (chi 2) and relative risk (RR) analyses. In 294 bulls there were 123 cases of respiratory disease. Seroconversion to bovine respiratory syncytial virus (RR = 4.7, chi 2 = 96.3, P less than 0.001) and adenovirus A (RR = 1.8, chi 2 = 8.9, P less than 0.001) and adenovirus B (RR = 1.9, chi 2 = 5.6, P less than 0.05) were significantly associated with clinical respiratory disease. There was evidence that prior exposure to respiratory syncytial virus (RR = 0.4, chi 2 = 9.8, P less than 0.01) Pi3 (RR = 0.4, chi 2 = 12.8, P less than 0.01) and adenovirus A (RR = 0.7, chi 2 = 7.5, P less than 0.01) conferred some protection against respiratory disease after arrival at the centre. It is concluded that vaccination before weaning, at least against bovine respiratory syncytial virus, would be beneficial.

Relationship of calf antibody status to disease and performance.

Three tests were used to measure the circulating immunoglobulin in 381 purchased calves as they entered a commercial calf-rearing unit. A correlation of 0.64 was found between the zinc sulphate turbidity (ZST) test and a quantitative latex agglutination test (LAT) measuring IgG1 (P less than 0.001). A qualitative version of the LAT related poorly to the quantitative version. The proportion of plasma samples identified by the quantitative LAT as having an IgG1 concentration of less than 5 g/litre which were incorrectly identified as positives (greater than or equal to 5 g/litre) by the qualitative LAT was 0.65. The proportion of plasma samples identified by the quantitative LAT as having a IgG1 concentration of greater than or equal to 5 g/litre which were incorrectly identified as negative (less than 5 g/litre) was 0.11. There was no statistically significant relationship between plasma IgG1 concentration and initial liveweight, subsequent overall daily liveweight gain or disease incidence (P greater than 0.05). Calves treated for infectious disease, particularly respiratory disease after weaning, had statistically significantly lower liveweight gains than healthy calves (P less than 0.001).